1. Field of the Invention
The invention relates to an optical sight, more particularly to an optical sight that facilitates reticle adjustment.
2. Description of the Related Art
As shown in FIG. 1 and FIG. 2, a conventional optical sight 1 includes an outer barrel 11, an ocular lens 12 mounted to one end 111 of the outer barrel 11, an objective lens 13 mounted to the other end 112 of the outer barrel 11, and a magnification unit 14 including an inner barrel 141 that is disposed tiltably in the outer barrel 11, and that extends between the ocular and objective lens units 12, 13. The conventional optical sight 1 further includes two adjustment units 16, and an elastic plate 17. The magnification unit 14 is provided with a reticle 15 visible through the ocular lens unit 12. The adjustment units 16 are mounted on the outer barrel 11. The elastic plate 17 is interposed between the inner and outer barrels 141, 11 to provide an urging force on the inner barrel 141 to abut against the adjustment units 16, and is disposed equiangularly from the adjustment units 16. Each of the adjustment units 16 includes a bolt 161 extending radially through and engaging threadedly the outer barrel 11, and abutting against the inner barrel 141, and a removable protective casing 162 for concealing the bolt 161.
When a user rotates the bolts 161 of the adjustment units 16 relative to the outer barrel 11, the bolts 161 respectively adjust position of the inner barrel 141 inside the outer barrel 11 in first and second directions (X1), (Y1) that are perpendicular to each other. The urging force exerted by the elastic plate 17 on the inner barrel 141 helps secure the inner barrel 141 in place after the adjustments has been made. In this manner, position of the reticle 15, which corresponds to aiming position of the optical sight, is adjusted. Although the elastic plate 17 is capable of exerting the urging force on the inner barrel 141, it has several drawbacks that require improvement during actual use.
Since the elastic plate 17 experiences fatigue after it has been in use for a period of time, the urging force exerted by the elastic plate 17 on the inner barrel 141 diminishes with time. Therefore, the position of the inner barrel 141 inside the outer barrel 11 often requires re-adjustments after the conventional optical sight 1, which is usually attached to a firearm (not shown), experiences recoil or intense vibration due to gunfire by the firearm. This re-adjustment of the position of the inner barrel 141 is inconvenient and troublesome.
Another type of conventional optical sight includes a fastening component (not shown) for securing the inner barrel 141 in place after the adjustment of the position of the inner barrel 141 in the outer barrel 11 by the adjustment units 16 is completed. Although the fastening component is capable of maintaining the position of the inner barrel 141 in the outer barrel 11, it is required to loosen the fastening component before each adjustment of the position of the inner barrel 141, and to tighten the fastening component after each adjustment is completed. The inconvenience aspect of the previous conventional optical sight 1 is obviously not improved with the use of the fastening component.